Puccinia pulverulenta  

Spermogonia scattered among the aecidia, yellowish.
Aecia hypophyllous (rarely also epiphyllous on heavily infected leaves), scattered copiously over the ± entire leaf surface. Peridium white, cupulate, the margins becoming revolute. Aeciospores 16-26 µm in length and 13-22 µm diam., subglobose to cylindric-ellipsoidal, orange, thin-walled, delicately verruculose.
Uredinia hypophyllous, scattered or sometimes confluent, with a floury appearance, chestnut brown. Urediniospores 23.5-29.5 x 16-25 µm, subglobose to obovoid, very thick-walled, chestnut brown, usually with two germ pores, rather remotely echinulate, with spines 1.5-2 µm tall and ca 1 µm diam. at the base.
Telia hypophyllous, in clusters, the overlying leaf tissue soon falling away to expose the teliospores, dark brown. Teliospores on hyaline, often eccentric deciduous pedicels 5-6 µm diam., 27-32 x 16-19 µm, cylindrical to obovoid-cylindrical, sometimes strongly constricted at the median to submedian septum, both ends rounded, very thick-walled (to 2.5 µm thick overall and 3.5-4 µm thick at the apex, the upper cell with an apical and usually also a lateral pore 4-5 µm diam., the lower cell with 1 (-2) lateral pores 4-5 µm diam., smooth or faintly verruculose.